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Data as of 2026-10-28
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Built 2026-10-28 (28 October 2026)

CAISO Demand Forecast Accuracy: Error, Bias and Worst Miss, 28 September to 28 October 2026

The day-ahead demand forecast for CAISO was off by 7.7% on average (mean absolute percentage error) over 719 hours from 28 September to 28 October 2026, and 63% of hours landed within 5% of the reading. Its bias was -6.5%: it ran low on average, an under forecast. The largest miss was 9,702 MW (33.3%) too low at 14 Oct 2026, 11:00 PDT (UTC-07:00). Dates and times are local (America/Los_Angeles).

Key Facts

  • The day-ahead demand forecast for CAISO was off by 7.7% on average (mean absolute percentage error) over 719 hours from 28 September to 28 October 2026, and 63% of hours landed within 5% of the reading. Its bias was -6.5%: it ran low on average, an under forecast. The largest miss was 9,702 MW (33.3%) too low at 14 Oct 2026, 11:00 PDT (UTC-07:00).
  • Across 53 US grids ranked by average error over their own latest 30 day windows, CAISO came 39 (1 is the smallest error).
  • On average the forecast differed from reported demand by 2,312 MW, against average demand of 28,713 MW.
  • The forecast was above reported demand in 30% of compared hours.

Forecast Error at a Glance

719 hours from 28 September to 28 October 2026
Average error7.7%
Bias-6.5%
Hours within 5%63%
Worst miss9,702 MW

Average error is the mean absolute percentage gap between the forecast and reported demand. Bias is the signed mean (-1,921 MW per hour on average): the forecast ran low on average, an under forecast. The worst miss was 9,702 MW (33.3%) too low at 14 Oct 2026, 11:00 PDT (UTC-07:00): forecast 19,442 MW, reported 29,144 MW.

Source: U.S. Energy Information Administration (EIA). (US Government work, public domain) Data as of 2026-10-28. Accuracy is computed by World Power Monitor from the operator's hourly forecast and reported demand.

Forecast and Reported Demand, Last 7 Days

Local time, to 28 Oct 2026, 04:00 PDT (UTC-07:00)
CAISO day-ahead demand forecast and reported demand by hour Hourly reported demand and the day-ahead forecast for CAISO over the last 7 days of the window, to 28 Oct 2026, 04:00 PDT (UTC-07:00). Gaps are hours with a missing, zero or implausible report. 0 10,000 20,000 30,000 40,000 21 Oct, 05:0022 Oct, 05:0023 Oct, 05:0024 Oct, 05:0025 Oct, 05:0026 Oct, 05:0027 Oct, 05:00
Hourly reported demand and the day-ahead forecast for CAISO over the last 7 days of the window, to 28 Oct 2026, 04:00 PDT (UTC-07:00). Gaps are hours with a missing, zero or implausible report.
Data to 2026-10-28
Show the data table (168 rows)
Local hourReported demandDay-ahead forecast
21 Oct, 05:0022,680 MW22,183 MW
21 Oct, 06:0024,119 MW24,074 MW
21 Oct, 07:0025,463 MW25,391 MW
21 Oct, 08:0026,689 MW25,749 MW
21 Oct, 09:0027,223 MW25,336 MW
21 Oct, 10:0028,054 MW24,981 MW
21 Oct, 11:0028,100 MW24,724 MW
21 Oct, 12:0027,970 MW24,655 MW
21 Oct, 13:0029,135 MW25,228 MW
21 Oct, 14:0030,668 MW26,216 MW
21 Oct, 15:0030,353 MW27,050 MW
21 Oct, 16:0029,340 MW27,782 MW
21 Oct, 17:0028,719 MW28,564 MW
21 Oct, 18:0028,426 MW29,154 MW
21 Oct, 19:0027,990 MW28,728 MW
21 Oct, 20:0027,279 MW27,859 MW
21 Oct, 21:0026,360 MW27,051 MW
21 Oct, 22:0025,050 MW25,564 MW
21 Oct, 23:0024,081 MW24,082 MW
22 Oct, 00:0023,599 MW23,539 MW
22 Oct, 01:0022,730 MW22,514 MW
22 Oct, 02:0022,219 MW21,652 MW
22 Oct, 03:0021,912 MW21,174 MW
22 Oct, 04:0021,362 MW21,331 MW
22 Oct, 05:0022,295 MW22,315 MW
22 Oct, 06:0023,817 MW24,172 MW
22 Oct, 07:0024,902 MW25,580 MW
22 Oct, 08:0026,012 MW25,798 MW
22 Oct, 09:0026,097 MW25,258 MW
22 Oct, 10:0027,044 MW24,632 MW
22 Oct, 11:0026,888 MW23,938 MW
22 Oct, 12:0027,941 MW23,482 MW
22 Oct, 13:0029,146 MW23,424 MW
22 Oct, 14:0029,313 MW23,627 MW
22 Oct, 15:0028,721 MW24,320 MW
22 Oct, 16:0027,035 MW25,027 MW
22 Oct, 17:0026,698 MW26,166 MW
22 Oct, 18:0027,207 MW27,078 MW
22 Oct, 19:0027,071 MW27,140 MW
22 Oct, 20:0026,261 MW26,435 MW
22 Oct, 21:0025,554 MW25,929 MW
22 Oct, 22:0024,358 MW24,772 MW
22 Oct, 23:0023,265 MW23,427 MW
23 Oct, 00:0022,779 MW22,145 MW
23 Oct, 01:0021,371 MW21,234 MW
23 Oct, 02:0020,870 MW20,457 MW
23 Oct, 03:0021,144 MW19,991 MW
23 Oct, 04:0020,942 MW20,200 MW
23 Oct, 05:0022,193 MW21,220 MW
23 Oct, 06:0023,689 MW23,208 MW
23 Oct, 07:0024,991 MW24,563 MW
23 Oct, 08:0026,845 MW24,472 MW
23 Oct, 09:0028,665 MW23,617 MW
23 Oct, 10:0029,256 MW22,499 MW
23 Oct, 11:0028,740 MW21,587 MW
23 Oct, 12:0028,837 MW20,957 MW
23 Oct, 13:0028,517 MW20,827 MW
23 Oct, 14:0027,656 MW21,295 MW
23 Oct, 15:0026,858 MW22,281 MW
23 Oct, 16:0024,821 MW23,433 MW
23 Oct, 17:0025,091 MW25,071 MW
23 Oct, 18:0026,015 MW26,023 MW
23 Oct, 19:0025,889 MW25,858 MW
23 Oct, 20:0025,045 MW25,213 MW
23 Oct, 21:0024,678 MW24,851 MW
23 Oct, 22:0023,797 MW23,900 MW
23 Oct, 23:0022,426 MW22,679 MW
24 Oct, 00:0022,194 MW21,834 MW
24 Oct, 01:0021,226 MW20,844 MW
24 Oct, 02:0020,490 MW20,019 MW
24 Oct, 03:0020,217 MW19,468 MW
24 Oct, 04:0019,983 MW19,471 MW
24 Oct, 05:0020,415 MW19,784 MW
24 Oct, 06:0020,688 MW20,657 MW
24 Oct, 07:0021,116 MW21,252 MW
24 Oct, 08:0022,895 MW20,556 MW
24 Oct, 09:0024,814 MW19,045 MW
24 Oct, 10:0024,996 MW17,392 MW
24 Oct, 11:0024,807 MW16,179 MW
24 Oct, 12:0024,509 MW15,642 MW
24 Oct, 13:0024,666 MW15,974 MW
24 Oct, 14:0024,632 MW17,050 MW
24 Oct, 15:0024,163 MW18,955 MW
24 Oct, 16:0022,914 MW21,230 MW
24 Oct, 17:0024,231 MW23,639 MW
24 Oct, 18:0025,362 MW24,887 MW
24 Oct, 19:0025,177 MW24,857 MW
24 Oct, 20:0024,537 MW24,294 MW
24 Oct, 21:0024,003 MW23,852 MW
24 Oct, 22:0023,112 MW23,008 MW
24 Oct, 23:0021,904 MW21,903 MW
25 Oct, 00:0021,399 MW21,034 MW
25 Oct, 01:0020,463 MW20,188 MW
25 Oct, 02:0019,788 MW19,429 MW
25 Oct, 03:0019,336 MW19,042 MW
25 Oct, 04:0019,196 MW18,873 MW
25 Oct, 05:0019,287 MW19,040 MW
25 Oct, 06:0019,765 MW19,684 MW
25 Oct, 07:0020,287 MW19,988 MW
25 Oct, 08:0022,668 MW19,351 MW
25 Oct, 09:0025,143 MW17,925 MW
25 Oct, 10:0024,461 MW16,545 MW
25 Oct, 11:0024,359 MW15,584 MW
25 Oct, 12:0023,947 MW15,283 MW
25 Oct, 13:0023,476 MW15,780 MW
25 Oct, 14:0024,877 MW17,250 MW
25 Oct, 15:0024,505 MW19,169 MW
25 Oct, 16:0024,036 MW21,424 MW
25 Oct, 17:0025,135 MW24,013 MW
25 Oct, 18:0026,419 MW25,386 MW
25 Oct, 19:0026,110 MW25,388 MW
25 Oct, 20:0025,296 MW24,731 MW
25 Oct, 21:0024,637 MW24,166 MW
25 Oct, 22:0023,376 MW23,062 MW
25 Oct, 23:0022,478 MW21,643 MW
26 Oct, 00:0021,638 MW20,860 MW
26 Oct, 01:0020,896 MW20,022 MW
26 Oct, 02:0020,676 MW19,412 MW
26 Oct, 03:0020,488 MW19,125 MW
26 Oct, 04:0020,971 MW19,458 MW
26 Oct, 05:0021,472 MW20,616 MW
26 Oct, 06:0023,067 MW22,644 MW
26 Oct, 07:0024,488 MW24,031 MW
26 Oct, 08:0026,770 MW23,637 MW
26 Oct, 09:0028,846 MW22,196 MW
26 Oct, 10:0027,632 MW20,709 MW
26 Oct, 11:0027,502 MW19,686 MW
26 Oct, 12:0027,428 MW19,521 MW
26 Oct, 13:0028,432 MW20,064 MW
26 Oct, 14:0028,288 MW21,386 MW
26 Oct, 15:0027,748 MW23,161 MW
26 Oct, 16:0026,423 MW25,231 MW
26 Oct, 17:0026,788 MW27,517 MW
26 Oct, 18:0027,827 MW28,052 MW
26 Oct, 19:0027,274 MW27,527 MW
26 Oct, 20:0026,375 MW26,579 MW
26 Oct, 21:0025,604 MW25,758 MW
26 Oct, 22:0024,292 MW24,358 MW
26 Oct, 23:0022,862 MW22,798 MW
27 Oct, 00:0022,220 MW22,213 MW
27 Oct, 01:0021,206 MW21,251 MW
27 Oct, 02:0020,385 MW20,481 MW
27 Oct, 03:0020,548 MW20,132 MW
27 Oct, 04:0021,071 MW20,414 MW
27 Oct, 05:0021,748 MW21,498 MW
27 Oct, 06:0022,280 MW23,421 MW
27 Oct, 07:0024,589 MW24,641 MW
27 Oct, 08:0025,895 MW23,981 MW
27 Oct, 09:0028,681 MW22,613 MW
27 Oct, 10:0028,268 MW21,050 MW
27 Oct, 11:0027,805 MW19,870 MW
27 Oct, 12:0027,481 MW19,236 MW
27 Oct, 13:0027,720 MW19,663 MW
27 Oct, 14:0028,504 MW20,872 MW
27 Oct, 15:0027,569 MW22,593 MW
27 Oct, 16:0025,821 MW24,482 MW
27 Oct, 17:0026,128 MW26,455 MW
27 Oct, 18:0027,248 MW27,663 MW
27 Oct, 19:0026,841 MW27,372 MW
27 Oct, 20:0026,118 MW26,485 MW
27 Oct, 21:0025,583 MW25,868 MW
27 Oct, 22:0024,167 MW24,430 MW
27 Oct, 23:0022,926 MW22,952 MW
28 Oct, 00:0022,754 MW22,039 MW
28 Oct, 01:0021,921 MW21,048 MW
28 Oct, 02:0021,091 MW20,274 MW
28 Oct, 03:0020,561 MW19,921 MW
28 Oct, 04:0020,678 MW20,182 MW

Assumptions

  • Only hours with both a forecast and a positive demand reading count (719 of 720 hours in the window). Missing and zero values, and readings under 30% or over 3 times the grid's own median for the window, are treated as reporting faults and left out.
  • Error is (forecast minus reported demand) divided by reported demand; average error uses absolute values so high and low misses do not cancel. Bias keeps the sign and does cancel.
  • Reported demand is preliminary and may be revised. A 30 day window is a short sample and one heat wave or holiday can move these figures.
  • US figures are for the EIA balancing authority or region named on this page. US and European grids are ranked separately.
Cite this page
APA 7

World Power Monitor. (2026). CAISO Demand Forecast Accuracy: Error, Bias and Worst Miss. https://worldpowermonitor.com/forecast-accuracy/caiso/

Plain text

World Power Monitor. CAISO Demand Forecast Accuracy: Error, Bias and Worst Miss. Data as of 2026-10-28. Data from U.S. Energy Information Administration. https://worldpowermonitor.com/forecast-accuracy/caiso/

BibTeX 
@misc{wpm_forecast_accuracy_caiso_2026,
  title = {{CAISO Demand Forecast Accuracy: Error, Bias and Worst Miss}},
  author = {{World Power Monitor}},
  year = {2026},
  note = {Data as of 2026-10-28. Data from U.S. Energy Information Administration.},
  url = {https://worldpowermonitor.com/forecast-accuracy/caiso/}
}

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